The below blog, written by Stuart Ayles Performance Coach & Exercise Physiologist (BSc Hons), explores the fascinating connection between gut health and muscle function. Drawing on his background in exercise physiology, sport science, and nutrition, Stuart looks at how the gut microbiome influences muscle energy, recovery, and performance, and how everyday factors like diet and exercise can help support this important relationship. The blog is intended for educational purposes and to encourage healthy, evidence-based lifestyle choices.
Due to extensive research and favourable health benefit findings over the last decade, the bacteria that live in our intestines have become a hot subject and as such, extremely marketable, so let’s have a brief look at how beneficial our gut flora can be in relation to our muscles.
Our gut microbiome is a complex community of microorganisms in the digestive tract, which is increasingly being recognised for its influence on various aspects of health, from Mental Health to Immunity and Inflammation. However, an emerging area of research is how our microbiome interacts with Skeletal Muscle. This relationship between the gut microbiome and skeletal muscle, often referred to as the gut-muscle axis, highlights how our gut bacteria can profoundly influence muscle health, growth, function, repair and even may play a role in support muscle health as we age.
How do these minute organisms have such an influence you may ask, well let’s see….
The bacteria in our Gut break down nutrients, particularly dietary fibre, into metabolites like Short-Chain Fatty Acids (SCFAs) (acetate, butyrate, propionate), which our cells use for energy as well as other physiological functions. These SCFAs can directly impact muscle cells and influence pathways involved in glucose and fat metabolism, hence playing an important role in muscle energy production, and potentially affecting muscle mass.
A healthy gut microbiome helps maintain a strong intestinal barrier, preventing the absorption of harmful bacteria, endotoxins, and pathogens, into the bloodstream, all of which can trigger systemic inflammation and contribute to insulin resistance and muscle protein breakdown, ultimately affecting muscle mass and function.
The gut microbiome may also influence anabolic resistance, the decreased sensitivity of muscle cells to anabolic stimuli, potentially through its impact on gut-derived low-grade inflammation mentioned above, and amino acid availability for muscle protein synthesis, affecting the body’s natural processes of muscle maintenance and regeneration.
SCFAs, particularly butyrate, have been shown to enhance mitochondrial biogenesis, the process of creating new mitochondria, in skeletal muscle cells, thereby impacting muscle energetics and potentially improving muscle endurance.
The gut microbiota might also play a role in the proper development and function of the neuromuscular junction, the site of communication between nerve and muscle fibres, impacting muscle control and movement.
Research has shown that changes in the gut microbiota — such as reduced diversity and a decrease in short-chain fatty acid (SCFA)–producing bacteria — are associated with age-related muscle decline and other conditions linked to muscle loss. Imbalances in the gut ecosystem, often referred to as dysbiosis, can influence inflammation and muscle function, highlighting how a healthy and diverse microbiome may play an important role in supporting muscle strength and maintenance throughout life.
The microbiome, particularly the gut microbiome, plays a significant role in injury recovery by influencing the immune system, inflammation, and overall healing processes. A balanced microbiome can enhance the immune response, reduce inflammation, and may promote faster healing, while dysbiosis can hinder recovery. Our gut microbes produce Regulatory T Cells, which act as immune healers and contribute to muscle repair.
So now we can see the beneficial impact our gut microbiome has on our Skeletal Muscle system, surely, it’s obvious a “healthy gut” is vital for function, maintenance, growth & repair and therefore longevity. Supporting our gut microbiome is generally not difficult, and two ways of doing that are simply through dietary changes and exercise.
Dietary interventions aimed at improving the gut microbiota, such as increasing fibre intake, and the use of prebiotics (non-digestible compounds that promote the growth of beneficial bacteria) and probiotics (beneficial living microorganisms), have shown beneficial changes in muscle health in human studies.
Any form of exercise from Low Intensity to High Intensity, Resistance Training, Strength Training, Running, Cycling etc, can all positively influence the composition and diversity of the gut microbiota, creating a positive feedback loop within the gut-muscle axis.
So, in conclusion, the gut-muscle axis highlights a fascinating and significant connection between our gut health and muscle function. Maintaining a healthy and diverse gut microbiome through diet, exercise, and potentially other interventions offers a promising avenue for supporting muscle function and overall well-being. More research is needed to fully understand the intricacies of this relationship and translate these findings into clinically applicable interventions.
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